Coastal Waters Forecast
Issued by NWS Tiyan, Guam
Issued by NWS Tiyan, Guam
202 FZMY50 PGUM 170703 CWFGUM Coastal Waters Forecast for the Mariana Islands National Weather Service Tiyan GU 503 PM ChST Mon Aug 17 2026 Marianas Waters out to 40 nautical miles PMZ150-172245- 503 PM ChST Mon Aug 17 2026 .Synopsis for Marianas Waters... Gentle westerlies will continue to decrease to light and variable tonight for Saipan and Tinian followed by Guam and Rota after midnight. Combined seas of 4 to 6 feet will persist throughout the week, possibly building over the weekend. A wetter weekend may be in store depending on the development of Invest 92W. This situation will continue to be monitored closely. $$ PMZ151>154-172245- MARIANAS COASTAL WATERS- 503 PM ChST Mon Aug 17 2026 .TONIGHT...West wind 5 to 10 kt becoming light and variable after midnight. Seas 4 to 6 ft. Wave Detail: West 4 ft at 9 seconds, north 3 ft at 9 seconds, and west 2 ft at 4 seconds. Isolated thunderstorms. For Guam and Rota, scattered showers after midnight. .TUESDAY...Variable wind 5 kt. Seas 4 to 6 ft. Wave Detail: West 4 ft at 9 seconds and north 3 ft at 9 seconds. Scattered showers with isolated thunderstorms in the afternoon. .TUESDAY NIGHT...North wind 5 to 10 kt. Seas 4 to 6 ft. Wave Detail: West 4 ft at 9 seconds, north 3 ft at 9 seconds and north 2 ft at 4 seconds. Scattered showers with isolated thunderstorms. .WEDNESDAY...North wind 5 to 10 kt. Seas 4 to 6 ft. Wave Detail: West 4 ft at 9 seconds, north 3 ft at 9 seconds and north 2 ft at 4 seconds. Scattered showers with isolated thunderstorms. .WEDNESDAY NIGHT...Northeast wind 10 kt. Seas 4 to 6 ft. Wave Detail: West 4 ft at 9 seconds, north 3 ft at 9 seconds and northeast 2 ft at 4 seconds. Scattered showers with isolated thunderstorms. .THURSDAY AND FRIDAY...East wind 5 to 10 kt. Seas 4 to 6 ft. Wave Detail: West 4 ft at 9 seconds, northeast 4 ft at 9 seconds and northeast 2 ft at 4 seconds. Isolated thunderstorms. .SATURDAY...Southwest wind 5 to 15 kt. Seas 5 to 7 ft. Wave Detail: Northeast 5 ft at 10 seconds, west 3 ft at 9 seconds and southwest 3 ft at 4 seconds. A chance of showers. $$